Improvement in steam-boiler furnaces



UNITED STATES PATENT OFFICE.

SAMUEL KEYES, oE BENNINGToN, vEEMoNT.

IMPROVEMENT IN STEAM-BOILER FURACES.

Specification forming part of Lettere Patent No. 144,393, dated November11, 1873;l application filed J une 7, 1873.

To all whom t may concern:

Be it known that I, SAMUEL KEYES, of Bennington, in the county ofBennington and State of `Vermont, have invented certain Improvements inSteam-Boiler Furnaces, of which the following is a specication,reference being had to the accompanying drawing.

This invention consists of the combination of devices, as hereinafterdescribed, for heating a horizontal boiler to generate steam therein,and superheat the steam in the upper part of the boiler, for equalizingthe heat of, and lessening the radiation, conduction, and waste of heatfrom the outer surface of, the furnace around the boiler, and forproducing a heated current of atmospheric air, and conducting the sameinto the draft-chamber under the fuel-grate of the rechamber of thefurnace. l In the aforesaid drawing, Figure lis an elevation of acentral vertical section, at the line z z in Figs. 2, 3, and 4, of acombined steamboiler and furnace which embodies my invention. Fig. 2 isan elevation of a section of the same at the line w w, and viewed in thedirection of the arrow y in Figs. l and 4. Fig. 3 is an elevation of asection of the same at the line a; w in Fig. l, viewed in the directionof the arrow y. Fig. 4 is a plan of a horizontal section of the furnaceat the line e c.

A is a steam-boiler. B is a fire-chamber under the forward portion ofthe boiler. C is a gas-flue extending from the rechamber along thebottom and sides of the boiler, and in afn, by which the ash-pit can beclosed, as represented in Fig. 1. The fire-chamber B has a grate in itsbottom over the ash-pit, and has a door, o, by which the fire-chamber isclosed. The gas-flue C has communication, through the chamber I andboiler-flue q, with a draft-pipe or chimney, It. The airspace I may ormay not extend across the end or ends of the furnace, and may or may nothave a passage or passages, s, under the casing of the gas-flue belowthe boiler. The extension of the gasflue C in a sheet over the top ofthe boiler keeps the steam hot therein, and the air-space I retards theconduction of heat from the flue G to the outer surface of the sides andtop of the furnace, whether the apertures e, g, and k, or any of them,are either permanentlyr or temporarily closed or open. When the aperturee is open, and the apertures g or 7c, or g and k, are open to theexternal air, or to the ash-pit M, when the latter is wide open, acurrent of air will enter the lower part of the space I by the aperturesg or k, or g and k, and will be warmed or heated in, and will passupward and rearward through, the sheet-space I, and will pass outthrough the aperture e, so that the heating of the sides and top of theouter casing H of the furnace will`thereby be more effectually preventedthan when the said aperture or apertures shall be closed, or the space Ioccupied by confined air, and at the same time the current of warm orheated air issuing from the aperture e can be conducted off by a pipeand used to warm a distant apartment, or for other purposes.

B and ash-pit M are closed, and the apertures e and k are open, orpartly open, as indicated in Fig. 1, and the `apertures g g are closed,or do not exist, the draft through the gas-iiue C draws a current of airthrough the aperture e into, and downward through, the

the damper or dampers for l,- and the same.

current of air, in passing down through the space I, eectually preventsthe heating of the outer casing Hof the furnace.l When the aperture e isclosed, and one of the apertures g g is open and the other closed, andthe passage k which is nearestto the open one of the apertures g g isclosed, while the other passage k is open, and the doors-91lando of thechamp bers M and B are closed, in that case the When the fire-chamberdraft of a lire in the chamber B will draw external air through the openone of the apertures g g into the lower part of one leg of thesheet-like space I, and upward therein to and through the upper portionthereof, and thence downward through the other leg of the space I, andthrough the open one of the passages k 7c, into the chamber M, andthence upward through the burning fuel on the grated bottom of thechamber BI By thus merely having the lower part of one leg of the spaceI open to the external air by an aperture, g, and the lower part of theother leg of the space I in communication with the chamber M by apassage, k, the external air is admitted by the aperture g into thechamber I, wherein it absorbs the heat given oft' from the casing D ofthe ue C over the boiler,and is thence conducted into the chamber M bythe passage ls,

boiler, sheet-like space I over the flue G, cham ber M under thelire-chamber, and passages e and 7o 7c for directing external air intoand through the space I, and thence into the chamber M, substantially asdescribed.

SAMUEL KEYES.

Witnesses:

ABRAHAM B. GARDNER, THoMAs WHITE.

